Plant cells come in a range of sizes, but they are generally between 10 and 100 microns, with most toward the higher end of the range.
Plant cells are often, but not always, larger than animal cells. Most are comparable in size. However, plant cell sizes are more variable than animal cell sizes on the individual level, because many plant cells contain large spaces that can shrink and grow as conditions change. These spaces, called vacuoles, can contain water, starch, pigments, toxins, or other substances.
The world's largest single-cell organism is actually a plant whose cells can grow to be 6 to 12 inches. This algae is also considered unusual because its huge cells are shaped much like the leaves of multicellular organisms.